java - Utdao.save(object) - java.lang.NullPointerException

标签 java spring web

以下错误(完整描述如下):

com.sun.faces.lifecycle.InvokeApplicationPhase execute WARNING: #{testeHibernate.save}: java.lang.NullPointerException javax.faces.FacesException: #{testeHibernate.save}

当我上传注册按钮时会发生这种情况，不允许我在数据库中输入值。

类别

UtilizadorDAO.java

package DAO;

import Classhiber.Utilizador;
import java.util.List;

public interface UtilizadorDAO {
    public void addutilizador (Utilizador ut);
    public List<Utilizador> findallutilizador();

}

UtilizadorDaoimpl.java

package Impl;

import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;

import Classhiber.Utilizador;
import DAO.UtilizadorDAO;

public class UtilizadorDAOimpl implements UtilizadorDAO {
    private SessionFactory sessionFactory;

    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }

    public void addutilizador(Utilizador ut) {
        Session session = this.sessionFactory.openSession();
        Transaction tx = session.beginTransaction();
        session.persist(ut);
        tx.commit();
        session.close();    }

    public List<Utilizador> findallutilizador() {
        Session session = this.sessionFactory.openSession();
        List<Utilizador> Utilizadorlist = session.createQuery("from Utilizador").list();
        session.close();        
        return Utilizadorlist;
    }


}

testeHibernate.java

import java.util.List;

import javax.faces.application.FacesMessage;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;
import javax.faces.bean.SessionScoped;
import javax.faces.context.FacesContext;
import Classhiber.Utilizador;
import DAO.UtilizadorDAO;
import Impl.UtilizadorDAOimpl;
@ManagedBean
@SessionScoped
public class TesteHibernate {

    public UtilizadorDAO utdao;

    private Utilizador utiliza;

        public TesteHibernate()
{
    utdao = new UtilizadorDAOimpl();
    utiliza = new Utilizador(); 
}
    public UtilizadorDAO getUtilizadorDAO() {
        return utdao;
    }

    public void setUtiliza(UtilizadorDAOimpl ut) {
        this.utdao = ut;
    }

    public Utilizador getUtiliza() {
        return utiliza;
    }

    public void setUtiliza(Utilizador utz) {
        this.utiliza = utz;
    }

    public void save() {
        // Calling Business Service
        utiliza.setIdUt(12);
        System.out.println(utiliza.getUser());
        System.out.println(utiliza.getPass());
        System.out.println(utiliza.getTip());

        utdao.addutilizador(utiliza);
    }
    }

Spring.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
        destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3307/xp" />
        <property name="username" value="root" />
        <property name="password" value="" />
    </bean>


<!-- Hibernate 4 SessionFactory Bean definition -->
<bean id="hibernate4AnnotatedSessionFactory"
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="annotatedClasses">
            <list>
                <value>Classhiber.Utilizador</value>
            </list>
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
                <prop key="hibernate.current_session_context_class">thread</prop>
                <prop key="hibernate.show_sql">false</prop>
            </props>
        </property>
    </bean>


    <bean id="UtilizadorDAOimpl" class="Impl.UtilizadorDAOimpl">
        <property name="sessionFactory" ref="hibernate4AnnotatedSessionFactory" />
    </bean>
</beans>

index.xhtml

<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:p="http://primefaces.org/ui">
<h:head>
    <script name="jquery/jquery.js" library="primefaces"></script>
    <title>Register Utilizador</title>
</h:head>
<h:form>
    <p:growl id="messages"></p:growl>
    <p:panelGrid columns="2">
        <p:outputLabel value="Enter Utilizdor User:"></p:outputLabel>
        <p:inputText value="#{testeHibernate.utiliza.user}"></p:inputText>
        <p:outputLabel value="Enter Utilizador Pass:"></p:outputLabel>
        <p:inputText value="#{testeHibernate.utiliza.pass}"></p:inputText>
        <p:outputLabel value="Enter Utilizador tip"></p:outputLabel>
        <p:inputText value="#{testeHibernate.utiliza.tip}"></p:inputText>                     
    </p:panelGrid>
    <p:commandButton value="Register" action="#{testeHibernate.save}" ></p:commandButton>
</h:form>
</html>

错误

Ago 28, 2015 6:23:44 PM com.sun.faces.lifecycle.InvokeApplicationPhase execute
WARNING: #{testeHibernate.save}: java.lang.NullPointerException
javax.faces.FacesException: #{testeHibernate.save}: java.lang.NullPointerException
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118)
    at javax.faces.component.UICommand.broadcast(UICommand.java:315)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:957)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
Caused by: javax.faces.el.EvaluationException: java.lang.NullPointerException
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
    ... 26 more
Caused by: java.lang.NullPointerException
    at Impl.UtilizadorDAOimpl.addutilizador(UtilizadorDAOimpl.java:21)
    at TesteHibernate.save(TesteHibernate.java:46)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:278)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:273)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
    ... 27 more

1245
Ago 28, 2015 6:23:44 PM com.sun.faces.context.AjaxExceptionHandlerImpl handlePartialResponseError
SEVERE: javax.faces.el.EvaluationException: java.lang.NullPointerException
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
    at javax.faces.component.UICommand.broadcast(UICommand.java:315)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:957)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
    at Impl.UtilizadorDAOimpl.addutilizador(UtilizadorDAOimpl.java:21)
    at TesteHibernate.save(TesteHibernate.java:46)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:278)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:273)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
    ... 27 more

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    id="WebApp_ID" version="2.5" metadata-complete="true">
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>/faces/*</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.xhtml</url-pattern>
    </servlet-mapping>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

谢谢。 (如果您有任何严重的编程错误，请原谅，但我正在学习)

最佳答案

由于您使用的是 CDI，因此您应该在用 @PostConstruct 注释的方法中初始化您的内容

因此您可以将 testeHibernate.java 中的构造函数替换为

@PostConstruct
public void init() {
    utdao = new UtilizadorDAOimpl();
    utiliza = new Utilizador(); 
}

CDI中还有一个类何时被拆除的注解，即@PreDestroy

此外，坚持编码约定并使用开头大写字母将文件命名为与类名相同的名称可能会派上用场。

关于java - Utdao.save(object) - java.lang.NullPointerException，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32276638/

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